rbenv로 ruby2.5.0 설치

$ brew upgrade ruby-build
Updating Homebrew...
==> Auto-updated Homebrew!
Updated 2 taps (homebrew/core, homebrew/php).

...中略

==> Summary
🍺  /usr/local/Cellar/openssl/1.0.2n: 1,792 files, 12.3MB
==> Installing ruby-build
==> Downloading https://github.com/rbenv/ruby-build/archive/v20171226.tar.gz
==> Downloading from https://codeload.github.com/rbenv/ruby-build/tar.gz/v20171226
######################################################################## 100.0%
==> ./install.sh
🍺  /usr/local/Cellar/ruby-build/20171226: 373 files, 192KB, built in 3 seconds

$ rbenv install 2.5.0
ruby-build: use openssl from homebrew
Downloading ruby-2.5.0.tar.bz2...
-> https://cache.ruby-lang.org/pub/ruby/2.5/ruby-2.5.0.tar.bz2
Installing ruby-2.5.0...
ruby-build: use readline from homebrew
Installed ruby-2.5.0 to /Users/nishihara/.rbenv/versions/2.5.0

$ rbenv local 2.5.0